Many types of input devices are presently available for performing operations in a computing system, such as buttons or keys, mice, trackballs, joysticks, touch sensor panels, touch screens and the like. Touch screens, in particular, are becoming increasingly popular because of their ease and versatility of operation as well as their declining price. Touch screens can include a touch sensor panel, which can be a clear panel with a touch-sensitive surface, and a display device such as a liquid crystal display (LCD) that can be positioned partially or fully behind the panel so that the touch-sensitive surface can cover at least a portion of the viewable area of the display device. Touch screens can allow a user to perform various functions by touching the touch sensor panel using a finger, stylus or other object at a location dictated by a user interface (UI) being displayed by the display device. In general, touch screens can recognize a touch event and the position of the touch event on the touch sensor panel, and the computing system can then interpret the touch event in accordance with the display appearing at the time of the touch event, and thereafter can perform one or more actions based on the touch event.
Mutual capacitance touch sensor panels can be formed from a matrix of drive and sense lines of a substantially transparent conductive material such as Indium Tin Oxide (no), often arranged in rows and columns in horizontal and vertical directions on a substantially transparent substrate. In some touch sensor panel designs, the substantially transparent drive and/or sense lines can be routed to one edge of the substrate for off-board connections using metal traces in the border areas of the substrate where transparency may not be required. Because these metal traces are thin, low resistance conductive material may be needed. To create such traces, multiple layers of conductive material may be needed to adhere low resistance material to the substrate and form the traces. However, the processing of multiple layers can increase manufacturing costs. In addition, there can be reliability issues involved in the fabrication of stackups of these thin metal layers. Furthermore, these thin metal traces do not provide maximum shielding from noise sources such as the LCD.